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R Programming Articles
Page 122 of 174
R programming to find the sum of corresponding elements in all matrix’s stored in a list.
To find the sum of corresponding elements in all matrix’s stored in a list in R, we can use Reduce function with plus sign. For Example, if we have a list called LIST that contains multiple matrices and we want to find the sum of corresponding elements then we can use the command given below −Reduce("+",LIST)Check out the below Examples to understand how it works.Example 1To find the sum of corresponding elements in all matrix’s stored in a list in R, use the following snippet −List
Read MoreHow to find the sum of all array elements in R?
To find the sum of all array elements in R, we can use Reduce function with plus sign. For Example, if we have an array called ARRAY and we want to find the sum of all values in this array then we can use the command Reduce("+",ARRAY).Check out the below Examples to understand how it works.Example 1To find the sum of all array elements in R use the snippet given below −Array1
Read MoreExtract a data frame column values as a vector by matching a vector in R.
To extract a data frame column values as a vector by matching a vector in R, we can use subsetting with %in% operator.For Example, if we have a data frame called df having a column say C and a vector V and we want to extract values in C if they match with V then we can use the command given below −df[df$C %in% V,"C"]Example 1Following snippet creates a sample data frame and vector −x1
Read MoreHow to change the name of single column using setNames in R?
To change the name of single column using setNames, we would need to specify the column name that needs to be changed.For example, if we have a data frame called df that contains three columns say Var1, var2, and Var3 and we want to change var2 to Var2 then we can use the command as follows −setNames(df,replace(names(df),names(df)=="var2","Var2"))Example 1Following snippet creates a sample data frame −x
Read MoreHow to add single quotes to strings in an R data frame column?
To add single quotes to strings in an R data frame column, we can use paste0 function. This will cover the strings with single quotes from both the sides but we can add them at the initial or only at the last position.To add them on both the sides, we can use the following syntax −Data_frame$Column
Read MoreHow to stop default printing of large numbers in R?
When we write a long number in R, by default the printed output of that number is in scientific notation. To stop this printing behavior we can use sprint function.For example, if we have a data frame called df that contains a column say X having long numbers then we can stop printing of these numbers in scientific notation by using the below given command −df$X
Read MoreHow to associate a character to numbers in an R data frame column?
Sometimes a variable has a character associated with the numerical values such as variable name etc. If we want to associate a character to numbers then paste0 function can be used.For example, if we have a data frame called df that contains a column say X then we can associate X to each value in the column by using the command given below −df$X
Read MoreHow to remove only the first duplicate row by group in an R data frame?
To remove only the first duplicate row by group, we can use filter function of dplyr package with duplicated function.For example, if we have a data frame called df that contains a grouping column say Grp then removal of only first duplicate row by group can be done by using the below command as follows −df%>%group_by(Grp)%>%filter(duplicated(Grp)|n()==1)Example 1Following snippet creates a sample data frame −Group
Read MoreHow to sort an R data frame rows in alphabetical order?
If we have string data stored in R data frame columns then we might want to sort the data frame rows in alphabetical order. This can be done with the help of apply and sort function inside transpose function.For example, if we have a data frame called df that contains string data then sorting of df in alphabetical order can be done by using the below given command −t(apply(df,1,sort))Example 1Following snippet creates a sample data frame −x1
Read MoreHow to find the percentage of missing values in each column of an R data frame?
To find the percentage of missing values in each column of an R data frame, we can use colMeans function with is.na function. This will find the mean of missing values in each column. After that we can multiply the output with 100 to get the percentage.Check out the below given examples to understand how it can be done.Example 1Following snippet creates a sample data frame −x1
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